A temperature sensor determines a temperature Tc of an LSI chip by comparing a reference voltage VREF independent of the temperature, and temperature sensing voltage VTS dependent on the temperature with each other. For example, a reference voltage VREF is divided into 2N−1 intermediate voltages, and at which point between the 2N−1 intermediate voltages the temperature sensing voltage VTS is positioned is compared by using 2N−1 comparators. The comparison result becomes, for example, N-bit temperature data indicating the temperature Tc of the LSI chip.
However, the temperature sensor carries out comparison between the reference voltage VREF, and temperature sensing voltage VTS simultaneously by using the 2N−1 comparators. As a result, first, the size of the temperature sensor becomes large, and the large size of the temperature sensor becomes a restriction on determining the layout in the LSI chip. Second, variations in performance of the 2N−1 comparators occur, and the variations become a cause of deterioration of the performance of the temperature sensor. In order to avoid this, it is sufficient if the size of the 2N−1 comparators is made larger. However, in this case, a problem that the size of the temperature sensor becomes larger occurs. Third, when the size of the comparators is made larger, the capacity concomitant with each of the comparators becomes larger, a waiting-time to the comparison to be carried out by these comparators is enabled occurs, and the time to detection of the temperature TC becomes longer.